Patent GB-814219-A (GB)
Title: Improvements in or relating to the production of long chain dicarboxylic acids and glycols
IPC: C07C51/09
Filed: 1957-01-14
Abstract: A 1 : 8-octanedioic acid or 1 : 8-octanediol is obtained by hydrogenating, at a temperature within the range of 150 DEG  to 325 DEG  C. under a hydrogen pressure of at least 10 atmospheres, in a normally liquid inert organic reaction medium and in contact with a copper chromite-containing catalyst, a dilactone having in its ultraviolet spectrum a strong absorption line in the region of 3300 to 4400   and of the general formula C4(RR1)2O8 in which R and R1 are the same or different and each represents a hydrogen atom, a haloaryl, alkoxyaryl or monovalent hydrocarbon radical free from non-aromatic unsaturation and in which, when R and R1 are different, one of each is present in each lactone ring.  At temperatures below 225 DEG  C., preferably 160-200 DEG  C., the principal product is a 1 : 8 octanediol acid.  At temperatures above 225 DEG  C., preferably at 250-310 DEG  C., the product is a 1 : 8-octanediol. The preferred dilactone is [D 2:21(5H,51H) - bifuran]-5 : 51 - dione whereby the product is suberic acid at the low temperatures and octamethylene glycol at the higher temperatures. Suitable inert organic reaction media are cyclohexane, diethyl ether, toluene, xylene and benzene in amounts from equal parts to 100 times the weight of dilactone.  A suitable catalyst is copper chromite promoted with barium chromite, generally in an amount of at least 5 per cent, preferably at least 20 per cent, by weight of the dilactone.  Where an alkoxyaryl dilactone is used, the alkoxy radical has preferably not more than 12 carbon atoms and the aryl radical not more than 10 carbon atoms.  The preferred haloaryl radical is chloroaryl where the aryl radical has not more than 10 carbon atoms.  Monovalent hydrocarbon radicals preferably have not more than 12 carbon atoms, e.g. alkyl, aryl, aralkyl or cycloalkyl radicals of not more than 7 carbon atoms. Examples of such radicals are methyl, ethyl, octyl, decyl, dodecyl, phenyl, tolyl, xylyl, benzyl, cyclohexyl, naphthyl, methylcyclohexyl, methoxyphenyl, ethoxyphenyl, decyloxyphenyl, dodecyloxyphenyl, dodecyloxynaphthyl, chlorophenyl and chloronaphthyl.  The dilactone starting materials may be obtained by reacting an acetylene with carbon monoxide in the presence of a cobalt carbonyl catalyst as described in Specification 811,498.  In examples: (1) the dilactone, [D 2:21(5H,51H)-bifuran]-5 : 51-dione, copper barium chromite catalyst and dioxane, are shaken at 290 DEG  C. with hydrogen at 2500-3000 lb/square inch for 3 1/2 hours to yield octamethylene glycol, characterized by conversion to the bis-N-phenyl carbamate, and 2-(4-hydroxybutyl) tetrahydrofuran as by-product, which was converted to an allophanate by reaction with cyanic acid in chloroform solution; (2)-(4) the procedure of (1) is repeated at different temperatures; the dilactone used in Examples (1) to (4) is prepared by charging acetylene, acetone and dicobalt octacarbonyl into a steel bomb and heating at 100 DEG  C. with carbon monoxide at 1000 atm. for 14-17 hours; (5) a solution of di-n-butyl-dilactone, i.e. <FORM:0814219/IV (b)/1> - 5 : 51-dione in dioxane is shaken at 275 DEG  C. with 3000 lb/square inch of hydrogen in the presence of copper barium chromite catalyst to yield 2,7-(or 3,6) dibutyl octane-1,8-diol; the di-n-butyldilactone is obtained by reaction of n-butylacetylene, acetone and cobalt carbonyl at 95-120 DEG  C. with carbon monoxide at 700-900 atm. for 18 hours; (6) a dioxane solution of the dilactone of (1) is hydrogenated at 190 DEG  C. and 2000-3000 lb/square inch for 3.5 hours with copper barium chromite catalyst to yield suberic acid; (7) the procedure of (6) is repeated at 160 DEG C. and 3000 lb/square inch with different amounts of reactants; (8) Example (6) is repeated at 200 DEG  C. under 3000 lb./square inch pressure with a magnesium promoted copper chromite catalyst.  The starting material of (1) may be replaced by dilactones in which R is phenyl, R1 is hydrogen; R and R1 are ethyl; R is n-butyl, R1 is hydrogen; R is b -naphthyl, R1 is hydrogen; R is chlorophenyl, R1 is hydrogen; R is o-methoxyphenyl and R1 is hydrogen to obtain the corresponding substituted 1 : 8-octanediols.  Similarly when the dilactones are substituted for the dilactone in (6) the corresponding substituted suberic acids are obtained.  Although the examples illustrate batch operation, the hydrogenation may be carried out as a continuous or semi-continuous up-flow, down-flow, co-current or counter-current vapour or liquid phase operation.